Work

Cultural Eutrophication Is Reflected in the Stable Isotopic Composition of the Eastern Mudsnail, Nassarius obsoletus

Year: 2017

Type: article

Abstract: In aquatic ecosystems, biological indicators are used in concert with nutrient concentration data to identify habitat impairments related to cultural eutrophication. This approach has been less commonly implemented in coastal areas due to the dominance of physical conditions in structuring biological assemblage data. Here, we describe the use of the stable isotopic composition of Nassarius obsoletus (Say), the eastern mudsnail, as an indicator of cultural eutrophication for 40 locations in coastal estuaries in New York. We found 15N enrichment in mudsnail tissue where watersheds had high population densities, land use patterns were more urbanized, and when sampling sites were adjacent to wastewater treatment plant discharges. Stable carbon isotopes were responsive to salinity and watershed forest cover, with more saline sites reflecting a predominantly C4 or algal carbon isotopic signature and more forested sites a lighter isotopic signature reflecting greater inputs of C3 terrestrial detrital carbon. Mudsnail nitrogen isotopic composition had a high level of separation between more affected and pristine watersheds (from 6.6 to 14.1‰), highlighting its utility as an indicator. We thus propose that stable isotope values of estuarine biota, such as the eastern mudsnail, can be used in concert with water quality data to identify areas where improvements in water quality are needed and can also be used to identify sources of detrital carbon to estuarine environments. Core Ideas We analyzed Nassarius obsoletus tissue and shell for δ15N and δ13C. δ15N values strongly reflected anthropogenic trophic enrichment from wastewater. δ13C values reflected C4 vs. C3 plant signatures on the basis of salinity and forest cover. Stable isotope signatures of estuarine biota are useful indicators of water quality.

Source: Journal of Environmental Quality

DOI: 10.2134/jeq2017.05.0214

Authors: Elizabeth Burke Watson, Katelyn Szura, Elisabeth Powell, Nicole Maher, Cathleen Wigand

Institutions: Drexel University, University of Rhode Island, The Nature Conservancy, Environmental Protection Agency

Language: English

Topic: Isotope Analysis in Ecology

Subfield: Ecology

Field: Environmental Science

Domain: Physical Sciences

SDGs: Life below water, Clean water and sanitation

Open Access status: green

Funder: U.S. Environmental Protection Agency